U.S. patent application number 12/064610 was filed with the patent office on 2009-06-11 for communication terminal apparatus, base station apparatus and reception quality reporting method.
This patent application is currently assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.. Invention is credited to Jinsong Duan, Atsushi Sumasu.
Application Number | 20090147869 12/064610 |
Document ID | / |
Family ID | 37771273 |
Filed Date | 2009-06-11 |
United States Patent
Application |
20090147869 |
Kind Code |
A1 |
Duan; Jinsong ; et
al. |
June 11, 2009 |
COMMUNICATION TERMINAL APPARATUS, BASE STATION APPARATUS AND
RECEPTION QUALITY REPORTING METHOD
Abstract
A communication terminal apparatus that can eliminate the waste
of reception quality report, suppress the interference of an
upstream network, perform an optimum assignment using a scheduling,
prevent the loss of resources, and ensure the fairness of
transmission assignment using the scheduling. In this apparatus, a
reception quality determining part (110) uses a pilot signal, which
is included in a received signal, to determine the reception
quality for each of subcarrier blocks. A CQI generating part (111)
generates CQIs each of which is the information indicative of a
result of the determination by the reception quality determining
part (110). A sorting part (112) sorts the CQIs in descending or
ascending order of the reception quality. A control part (113)
instructs, based on information about the number of subcarrier
blocks in which the CQIs have been transmitted, collision
information and scheduling information, the sorting part (112) with
respect to the number of subcarrier blocks in which the CQIs are
outputted.
Inventors: |
Duan; Jinsong; (Kanagawa,
JP) ; Sumasu; Atsushi; (Kanagawa, JP) |
Correspondence
Address: |
Christensen O'Connor Johnson Kindness PLLC
1420 5th Avenue, Suite 2800
Seattle
WA
98101
US
|
Assignee: |
MATSUSHITA ELECTRIC INDUSTRIAL CO.,
LTD.
Kadoma-shi, Osaka
JP
|
Family ID: |
37771273 |
Appl. No.: |
12/064610 |
Filed: |
August 22, 2005 |
PCT Filed: |
August 22, 2005 |
PCT NO: |
PCT/JP2005/015198 |
371 Date: |
February 22, 2008 |
Current U.S.
Class: |
375/260 |
Current CPC
Class: |
H04L 1/0029 20130101;
H04L 1/0027 20130101; H04L 1/0026 20130101 |
Class at
Publication: |
375/260 |
International
Class: |
H04L 27/28 20060101
H04L027/28 |
Claims
1. A communication terminal apparatus comprising: a received
quality measuring section that measures received quality for each
subcarrier block comprising a bundle of a plurality of subcarriers;
a received quality information generating section that generates
per subcarrier block received quality information comprising
information of the received quality measured in the received
quality measuring section; a transmission section that transmits
the received quality information generated in the received quality
information generating section to a communicating party; and a
control section that controls the number of subcarrier blocks for
which the transmission section transmits the received quality
information, based on the received quality information transmitted
from the transmission section and a result of scheduling using the
received quality information at the communicating party.
2. The communication terminal apparatus according to claim 1,
wherein the control section compares the number of subcarrier
blocks for which the transmission section transmits the received
quality information to the communicating party with the number of
subcarrier blocks actually allocated at the communicating party as
the result of scheduling, and controls the number of subcarrier
blocks.
3. The communication terminal apparatus according to claim 1,
wherein, when an allocation rate is smaller than a threshold, the
control section increases the number of subcarrier blocks to
transmit the received quality information as compared with a case
where the allocation rate is equal to or greater than the
threshold, the allocation rate being a ratio of the number of
subcarrier blocks actually allocated at the communicating party to
the number of subcarrier blocks for which the transmission section
transmits the received quality information to the communicating
party.
4. The communication terminal apparatus according to claim 1,
wherein the control section compares a transmission rate requested
in the received quality information transmitted to the
communicating party from the transmission section with a
transmission rate actually assigned at the communicating party as
the result of scheduling, and controls the number of subcarrier
blocks.
5. The communication terminal apparatus according to claim 1,
further comprising a reception section that receives ON/OFF control
information that commands to stop or resume transmission of the
received quality information when the number of communication
terminal apparatuses communicating with the communicating party is
equal to or larger than a predetermined number, wherein the control
section stops or resumes the transmission of the received quality
information by a command in the ON/OFF control information received
in the reception section.
6. A base station apparatus that is the communicating party
communicating with the communication terminal apparatus according
to claim 1, comprising: a reception section that receives the
received quality information of a plurality of communication
terminal apparatuses; a scheduling section that performs the
scheduling comprising processing for allocating resources per
subcarrier block within predetermined resources to a communication
terminal apparatus where the received quality of the received
quality information meets predetermined quality; and a reporting
section that reports a result of the scheduling in the scheduling
section to the communication terminal apparatuses.
7. A base station apparatus comprising: a reception section that
receives received quality information comprising information of
received quality for each subcarrier block comprising a bundle of a
plurality of subcarriers; a scheduling section that performs
scheduling comprising processing for allocating resources for each
subcarrier block to a communication terminal apparatus where the
received quality of the received quality information received in
the reception section meets predetermined quality; a control
section that controls the number of subcarrier blocks for which the
communication terminal apparatus transmits the received quality
information, based on the received quality information and a result
of the scheduling in the scheduling section; and a transmission
section that transmits number-of-report-subcarrier-block
information comprising information of the number of subcarrier
blocks controlled in the control section to the communication
terminal apparatus.
8. The base station apparatus according to claim 7, wherein the
control section compares the number of subcarrier blocks of the
received quality information received in the reception section with
the number of subcarrier blocks actually allocated in the
scheduling section, and controls the number of subcarrier
blocks.
9. The base station apparatus according to claim 7, wherein, when
an allocation rate is smaller than a threshold, the control section
increases the number of subcarrier blocks to transmit the received
quality information as compared with a case where the allocation
rate is equal to or greater than the threshold, the allocation rate
being a ratio of the number of subcarrier blocks actually allocated
in the scheduling section to the number of subcarrier blocks of the
received quality information received in the reception section.
10. The base station apparatus according to claim 7, wherein the
control section compares a transmission rate requested in the
received quality information received in the reception section with
a transmission rate actually assigned in the scheduling section,
and controls the number of subcarrier blocks.
11. The base station apparatus according to claim 7, further
comprising a collision measuring section that measures per
subcarrier block the number of pieces of the received quality
information received within predetermined time, wherein the control
section controls the number of subcarrier blocks based on the
number of pieces of the received quality information measured in
the collision measuring section.
12. The base station apparatus according to claim 11, wherein, when
the number of pieces of the received quality information measured
in the collision measuring section for the same subcarrier block is
equal to or larger than a threshold, the control section increases
the number of subcarrier blocks transmitting the received quality
information at the communication terminal apparatus that has
transmitted the number of pieces of the received quality
information equal to or larger than the threshold.
13. A communication terminal apparatus communicating with the base
station apparatus according to claim 7, comprising: a reception
section that receives the number-of-report-subcarrier-block
information; a received quality measuring section that measures the
received quality per subcarrier block; a received quality
information generating section that generates per subcarrier block
the received quality information comprising information of the
received quality measured in the received quality measuring
section; and a reporting section that reports pieces of the
received quality information corresponding to the number of
subcarrier blocks in the number-of-report-subcarrier-block
information among the received quality information generated in the
received quality information generating section.
14. The communication terminal apparatus according to claim 13,
wherein the reporting section reports the received quality
information of a larger number of subcarrier blocks than the number
of subcarrier blocks in the number-of-report-subcarrier-block
information.
15. The communication terminal apparatus according to claim 13,
further comprising a sort section that arranges the received
quality information generated in the received quality information
generating section in descending order of the received quality,
wherein the reporting section reports the received quality
information in descending order of the received quality among the
received quality information arranged in the sort section.
16. A received quality reporting method, comprising: measuring
received quality for each subcarrier block comprising a bundle of a
plurality of subcarriers; generating received quality information
comprising information of the measured received quality per
subcarrier block; transmitting the generated received quality
information to a base station apparatus from a communication
terminal apparatus; receiving in the base station apparatus the
received quality information of a plurality of communication
terminal apparatuses; performing scheduling comprising processing
for allocating resources per subcarrier block within predetermined
resources to a communication terminal apparatus where the received
quality of the received quality information meets predetermined
quality; reporting the scheduling result from the base station
apparatus to the communication terminal apparatuses; and
controlling in the communication terminal apparatus the number of
subcarrier blocks for which the received quality information is
transmitted based on the received quality information transmitted
to the base station apparatus from the communication terminal
apparatus and the scheduling result reported from the base station
apparatus.
Description
TECHNICAL FIELD
[0001] The present invention relates to a communication terminal
apparatus, base station apparatus and received quality reporting
method. More particularly, the present invention relates to a
communication terminal apparatus, base station apparatus and
received quality reporting method for reporting received quality in
uplink in a multicarrier transmission scheme.
BACKGROUND ART
[0002] In OFDM (Orthogonal Frequency Division Multiplex)
transmission, as shown in FIG. 1, there are cases where
communication quality of each subcarrier block (SCB1 to SCB8) is
different from one another due to frequency selective fading.
Further, in downlink OFDM transmission, channel states vary for
each communication terminal apparatus (UE), and so, by making each
communication terminal apparatus report the received quality to the
base station apparatus (Node B), the base station apparatus can
select per communication terminal apparatus only subcarriers having
good received quality and allocate transmission data. This method
is called frequency scheduling. In general, to perform frequency
scheduling, it is necessary that each communication terminal
apparatus measures received quality for a known pilot signal
transmitted from Node B, and reports received quality information
(CQI) based on the measurement result to the base station
apparatus. However, when the number of subcarriers forming an OFDM
signal is large, the report amount is enormous when the received
quality is reported for all subcarriers, and there is a problem
that uplink wireless resources are wasted.
[0003] For the above-mentioned problem, various reporting amount
reducing schemes have been proposed. For example, such a method is
known that a communication terminal apparatus does not report
received quality of a subcarrier with poor quality, and only
reports received quality of a subcarrier with good quality (for
example, Patent Document 1)
Patent Document 1: Japanese Patent Application Laid-Open No.
2001-351971
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0004] However, in the conventional apparatus, each communication
terminal apparatus independently judges subcarriers to report
received quality, and so there is a case where a plurality of
communication terminal apparatuses report the received quality of
the same subcarrier at the same time. In this case, the base
station apparatus cannot assign a plurality of communication
terminals to a single subcarrier, and therefore there are problems
that reports of received quality are wasted and the interference
increases in uplink. Further, there is a case where a subcarrier
for which no received quality is reported exists. In this case,
transmission allocation cannot be carried out based on the received
quality, there are problems that optimal allocation by scheduling
cannot be carried out and resources are lost. Furthermore, there is
a problem that it is difficult to set a criterion for reporting the
received quality from each communication terminal apparatus. For
example, such a case arises where a communication terminal
apparatus near the base station apparatus is generally good in
received quality and reports the received quality for all
subcarriers, and a communication terminal apparatus far from the
base station apparatus is generally poor in received quality and
does not report received quality. In this case, there is a problem
that transmission allocation by scheduling cannot be performed
fairly.
[0005] It is therefore an object of the present invention to
provide a communication terminal apparatus, base station apparatus
and received quality reporting method capable of reducing the
interference in uplink without wasting reports of received quality,
performing optimal allocation by scheduling, preventing resources
from being lost, and maintaining fairness of transmission
allocation by scheduling.
Means for Solving the Problem
[0006] A communication terminal apparatus of the present invention
adopts a configuration including: a received quality measuring
section that measures received quality for each subcarrier block
that is a bundle of a plurality of subcarriers; a received quality
information generating section that generates per subcarrier block
received quality information, which is information of the received
quality measured at the received quality measuring section; a
transmitting section that transmits the received quality
information generated in the received quality information
generating section to a communicating party; and a controlling
section that controls the number of subcarrier blocks for which the
transmission section transmits the received quality information,
based on the received quality information transmitted from the
transmission section and a result of scheduling using the received
quality information at the communicating party.
[0007] A base station apparatus of the present invention adopts a
configuration including: a reception section that receives received
quality information which is information of received quality for
each subcarrier block that is a bundle of a plurality of
subcarriers; a scheduling section that performs scheduling which is
processing for allocating resources for each subcarrier block to a
communication terminal apparatus where the received quality
information received in the reception section meets predetermined
quality; a control section that controls the number of subcarrier
blocks for which the communication terminal apparatus transmits the
received quality information, based on the received quality
information and a result of the scheduling in the scheduling
section; and a transmission section that transmits
number-of-report-subcarrier-block information which is information
of the number of subcarrier blocks controlled in the control
section to the communication terminal apparatus.
[0008] A received quality reporting method of the present invention
has the steps of: measuring received quality for each subcarrier
block that is a bundle of a plurality of subcarriers; generating
received quality information which is information of the measured
received quality for each subcarrier block; transmitting the
generated received quality information to a base station apparatus
from a communication terminal apparatus; receiving in the base
station apparatus the received quality information of a plurality
of communication terminal apparatuses; performing scheduling which
is processing for allocating resources per subcarrier block within
predetermined resources to a communication terminal apparatus where
the received quality of the received quality information meets
predetermined quality; reporting the scheduling result from the
base station apparatus to the communication terminal apparatuses;
and controlling in the communication terminal apparatus the number
of subcarrier blocks for which the received quality information is
transmitted based on the received quality information transmitted
to the base station apparatus from the communication terminal
apparatus and the scheduling result reported from the base station
apparatus.
ADVANTAGEOUS EFFECT OF THE INVENTION
[0009] According to the present invention, it is possible to reduce
the interference in uplink without wasting reports of received
quality, perform optimal allocation by scheduling, prevent
resources from being lost, and maintain fairness of transmission
allocation by scheduling.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 shows communication quality of each subcarrier;
[0011] FIG. 2 is a block diagram showing a configuration of a
communication terminal apparatus according to Embodiment 1 of the
present invention;
[0012] FIG. 3 is a block diagram showing a configuration of a base
station apparatus according to Embodiment 1 of the present
invention;
[0013] FIG. 4 shows a format of a signaling signal according to
Embodiment 1 of the present invention;
[0014] FIG. 5 shows a format of CQI report control information
according to Embodiment 1 of the present invention;
[0015] FIG. 6 shows transmission and reception of a signal between
the communication terminal apparatus and the base station apparatus
according to Embodiment 1 of the present invention;
[0016] FIG. 7 shows operations of the communication terminal
apparatus and the base station apparatus according to Embodiment 1
of the present invention;
[0017] FIG. 8 shows a format of CQI according to Embodiment 1 of
the present invention;
[0018] FIG. 9 shows a comparing circuit according to Embodiment 1
of the present invention;
[0019] FIG. 10 shows a method of forming a subcarrier block
according to Embodiment 1 of the present invention;
[0020] FIG. 11 shows the method of forming a subcarrier block
according to Embodiment 1 of the present invention;
[0021] FIG. 12 shows the format of CQI according to Embodiment 1 of
the present invention;
[0022] FIG. 13 shows a comparing circuit according to Embodiment 2
of the present invention;
[0023] FIG. 14 shows an instantaneous allocation rate and a
cumulative allocation rate according to Embodiment 3 of the present
invention;
[0024] FIG. 15 shows a subcarrier block for which communication
terminal apparatuses report CQI according to Embodiment 4 of the
present invention;
[0025] FIG. 16 shows a format of CQI according to Embodiment 4 of
the present invention;
[0026] FIG. 17 is a block diagram showing a configuration of a
communication terminal apparatus according to Embodiment 5 of the
present invention;
[0027] FIG. 18 is a block diagram showing a configuration of a base
station apparatus according to Embodiment 5 of the present
invention;
[0028] FIG. 19 shows operations of the communication terminal
apparatus and the base station apparatus according to Embodiment 5
of the present invention;
[0029] FIG. 20 shows a comparing circuit according to Embodiment 6
of the present invention;
[0030] FIG. 21 shows collisions in subcarrier blocks according to
Embodiment 6 of the present invention;
[0031] FIG. 22 is a block diagram showing a configuration of a
communication terminal apparatus according to Embodiment 7 of the
present invention;
[0032] FIG. 23 is a block diagram showing a configuration of a base
station apparatus according to Embodiment 7 of the present
invention; and
[0033] FIG. 24 shows CQI transmission timing of each communication
terminal apparatus according to Embodiment 7 of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] Embodiments of the present invention will be described in
detail below with reference to the accompanying drawings.
Embodiment 1
[0035] FIG. 2 is a block diagram showing the configuration of
communication terminal apparatus 100 according to Embodiment 1 of
the present invention.
[0036] Antenna 101 receives and outputs an OFDM signal to RF
reception section 102 and transmits a transmission signal inputted
from RF transmission section 119.
[0037] RF reception section 102 down-converts the received signal
inputted from antenna 101 from a radio frequency to a baseband
frequency and outputs the result to guard interval (hereinafter
"GI") removing section 103.
[0038] GI removing section 103 removes GIs from the received signal
inputted from RF reception section 102 and outputs the result to
fast Fourier transform (hereinafter "FFT") section 104.
[0039] FFT section 104 performs FFT on the received signal inputted
from GI removing section 103 and outputs the result to demodulation
section 105, scheduling information extracting section 107,
collision information extracting section 109 and received quality
measuring section 110.
[0040] Demodulation section 105 demodulates the received signal
inputted from FFT section 104 and outputs the result to error
correction decoding section 106.
[0041] Error correction decoding section 106 performs error
correction decoding on the received signal inputted from
demodulation section 105 and outputs the result as a received
signal.
[0042] Scheduling information extracting section 107 extracts
scheduling information included in the received signal inputted
from FFT section 104 and outputs the scheduling information to
selecting section 108 and control section 113. Herein, a subcarrier
block is a bundle of a plurality of subcarriers consecutive or
non-consecutive on the frequency axis, or a bundle of a plurality
of subcarriers of a predetermined size and a plurality of
transmission time intervals (hereinafter "TTI") in two dimensions
of the time axis and the frequency axis. Further, the scheduling
information is information of a result of scheduling that is
processing, performed in the base station apparatus, for allocating
resources for each subcarrier block to each communication terminal
apparatus based on the received quality information. Allocated
resources are, for example, the number of subcarrier blocks,
modulation scheme, coding rate, transmission rate and transmission
power.
[0043] Selecting section 108 extracts an MCS included in the
scheduling information inputted from scheduling information
extracting section 107, and based on the extracted MCS, controls
signal processing in error correction coding section 115,
modulation section 116 and IFFT section 117. More specifically,
selecting section 108 stores resource allocation information that
associates the MCS with the coding rate and modulation scheme, and
using the MCS included in the scheduling information, selects the
coding rate and modulation scheme by referring to the resource
allocation information. Then, selecting section 108 controls error
correction coding section 115 so that coding section 115 encodes a
transmission signal at the coding rate shown in the MCS. Further,
selecting section 108 controls modulation section 116 so that
modulation section 116 modulates the transmission signal with the
modulation scheme shown in the MCS. Furthermore, selecting section
108 controls inverse fast Fourier transform (hereinafter "IFFT")
section 117 so as to allocate the transmission signal to a
subcarrier block shown in the scheduling information.
[0044] Collision information extracting section 109 extracts
collision information included in the received signal inputted from
FFT section 104 and outputs the collision information to control
section 113. Herein, the collision information is information of
the number of communication terminal apparatuses that report CQI
for the same subcarrier block at the same time.
[0045] Received quality measuring section 110 measures received
quality using a pilot signal included in the received signal
inputted from FFT section 104. At this point, received quality
measuring section 110 measures the received quality per subcarrier
block. Then, received quality measuring section 110 outputs the
measurement result of the measured received quality to CQI
generating section 111.
[0046] Based on the measurement result inputted from received
quality measuring section 110, CQI generating section 111, which is
a received quality information generating means, generates CQI
(received quality information) that is information showing the
measurement result, and outputs the CQI to sort section 112 and
control section 113. At this point, CQI generating section 111
generates the CQI per subcarrier block.
[0047] Sort section 112 arranges the CQI inputted from CQI
generating section 111 in descending order of the received quality
or in ascending order of the received quality. Then, sort section
112 outputs the arranged CQI corresponding to the number designated
from control section 113, in descending order of the received
quality to multiplexing section 114.
[0048] Control section 113 designates the number of subcarrier
blocks to output the CQI to sort section 112, based on the
information of the number of subcarrier blocks for which the CQI
has been transmitted, which is inputted from CQI generating section
111, the collision information inputted from collision information
extracting section 109, and the scheduling information inputted
from scheduling information extracting section 107. In addition,
details of the operation of control section 113 will be described
later.
[0049] Multiplexing section 114 multiplexes a transmission signal
and the CQI inputted from sort section 112, generates a multiplexed
signal, and outputs the generated multiplexed signal to error
correction coding section 115.
[0050] Error correction coding section 115 performs error
correction coding on the multiplexed signal inputted from
multiplexing section 114 at a coding rate controlled in selecting
section 108. Then, error correction coding section 115 outputs the
multiplexed signal subjected to error correction coding to
modulation section 116.
[0051] Modulation section 116 modulates the multiplexed signal
inputted from error correction coding section 115 with a modulation
scheme controlled in selecting section 108 and outputs the result
to inverse fast Fourier transform (hereinafter "IFFT") section
117.
[0052] IFFT section 117 performs IFFT on the multiplexed signal
inputted from modulation section 116, allocates the transmission
signal to each subcarrier block, and thereby generates an OFDM
signal. At this point, IFFT section 117 allocates the transmission
signal to the subcarrier block controlled in selecting section 108,
that is, subcarrier block allocated by scheduling in the base
station apparatus. Then, IFFT section 117 outputs the generated
OFDM signal to GI inserting section 118.
[0053] GI inserting section 118 inserts GIs to the OFDM signal
inputted from IFFT section 117 and outputs the result to RF
transmission section 119.
[0054] RF transmission section 119 up-converts the OFDM signal
inputted from GI inserting section 118 from the baseband frequency
to the radio frequency and outputs the result to antenna 101.
[0055] A configuration of base station apparatus 200 will be
described next with reference to FIG. 3. FIG. 3 is a block diagram
showing the configuration of base station apparatus 200.
[0056] Antenna 201 receives and outputs an OFDM signal to RF
reception section 202 and transmits the OFDM signal inputted from
RF transmission section 217.
[0057] RF reception section 202 down-converts the received signal
inputted from antenna 201 from the radio frequency to the baseband
frequency, and outputs the result to GI removing section 203.
[0058] GI removing section 203 removes the GIs from the received
signal inputted from RF reception section 202 and outputs the
result to FFT section 204.
[0059] FFT section 204 performs FFT on the received signal inputted
from GI removing section 203 and outputs the result to demodulation
section 205.
[0060] Demodulation section 205 demodulates the received signal
inputted from FFT section 204 and outputs the result to error
correction decoding section 206.
[0061] Error correction decoding section 206 performs error
correction decoding on the received signal inputted from
demodulation section 205, outputs the result to CQI extracting
section 207, and outputs the result as a received signal.
[0062] CQI extracting section 207 extracts the CQI from the
received signal inputted from error correction decoding section
206, and outputs the extracted CQI to collision measuring section
208 and scheduling section 210.
[0063] Collision measuring section 208 measures collisions based on
the CQI inputted from CQI extracting section 207. More
specifically, collision measuring section 208 measures the number
of collisions for each subcarrier block. Then, collision measuring
section 208 outputs the measurement result of the number of
collisions to collision information generating section 209. Herein,
the collision is that a plurality of communication terminal
apparatuses transmit the CQI for the same subcarrier block at the
same time.
[0064] Based on the measurement result inputted from collision
measuring section 208, collision information generating section 209
generates collision information that is information showing the
measurement result, and outputs the collision information to
multiplexing section 212.
[0065] Scheduling section 210 performs scheduling based on the CQI
inputted from CQI extracting section 207. For example, scheduling
section 210 assigns a communication terminal apparatus that has
transmitted the CQI with the best received quality for each
subcarrier block, and selects an MCS of a combination of the coding
rate and modulation scheme corresponding to the transmitted CQI.
Then, scheduling section 210 outputs the information of the
subcarrier block assigned to each communication terminal apparatus
and MCS to scheduling information generating section 211.
[0066] Scheduling information generating section 211 generates
scheduling information including the information of the subcarrier
block assigned to each communication terminal apparatus and MCS
inputted from scheduling section 210 and outputs the scheduling
information to multiplexing section 212.
[0067] Multiplexing section 212 multiplexes the transmission
signal, pilot signal, collision information inputted from collision
information generating section 209, and scheduling information
inputted from scheduling information generating section 211,
generates a multiplexed signal, and outputs the generated
multiplexed signal to error correction coding section 213.
[0068] Error correction coding section 213 performs error
correction coding on the multiplexed signal inputted from
multiplexing section 212 and outputs the result to modulation
section 214.
[0069] Modulation section 214 modulates the multiplexed signal
inputted from error correction coding section 213 and outputs the
result to IFFT section 215.
[0070] IFFT section 215 performs IFFT on the multiplexed signal
inputted from modulation section 214, generates an OFDM signal, and
outputs the generated OFDM signal to GI inserting section 216.
[0071] GI inserting section 216 inserts GIs to the OFDM signal
inputted from IFFT section 215 and outputs the result to RF
transmission section 217.
[0072] RF transmission section 217 up-converts the OFDM signal
inputted from GI inserting section 216 from the baseband frequency
to the radio frequency and outputs the result to antenna 201.
[0073] Operations of communication terminal apparatus 100 and base
station apparatus 200 will be described next.
[0074] First, base station apparatus 200 determines the number of
subcarrier blocks to transmit the CQI, based on the number of
communication terminal apparatuses 100 communicating in the cell of
base station apparatus 200, QoS requested from communication
terminal apparatuses 100, transmission rate requested from
communication terminal apparatuses 100, data size of transmission
data requested from communication terminal apparatuses 100, the
distance between communication terminal apparatuses 100 and base
station apparatus 200 and the like. Communication terminal
apparatus 100 requests QoS, transmission rate and data size and
transmits CQI by transmitting a signaling signal to base station
apparatus 200. FIG. 4 shows a format of signaling signal 300
transmitted from communication terminal apparatus 100 to base
station apparatus 200. Signaling signal 300 is comprised of
requested QoS #301, which is information of QoS requested by
communication terminal apparatus 100, requested transmission rate
#302, which is information of a transmission rate requested by
communication terminal apparatus 100, requested data size #303,
which is information of a data size requested by communication
terminal apparatus 100 and CQI #304.
[0075] Base station apparatus 200 receiving signaling signal 300
determines the transmission rate of communication terminal
apparatus 100 based on the request of communication terminal
apparatus 100, and further determines the number of subcarrier
blocks assigned to communication terminal apparatus 100 that can
achieve the determined transmission rate. FIG. 5 shows a format of
CQI report control information 400 transmitted from base station
apparatus 200 to communication terminal apparatus 100. In FIG. 5,
number-of-subcarrier-block #401 is to specify the number of
subcarrier blocks to report, and report cycle #402 is to specify a
cycle of transmitting CQI. Further, report timing offset #403 is to
specify timing offset of report within the report cycle, and by
making the report timing different between communication terminal
apparatuses 100, it is possible to decrease report collisions
between communication terminal apparatuses 100 and reduce uplink
interference. Further, frequency range #404 is to specify a
frequency range of the subcarrier block that communication terminal
apparatus 100 should report, and by making the frequency range of
the subcarrier block to report different between communication
terminal apparatuses 100, it is possible to decrease report
collisions between communication terminal apparatuses 100.
Furthermore, command #405 to change the report subcarrier block is
to command communication terminal apparatus 100 to change the
subcarrier block number to report, and has an effect of dispersing
subcarrier blocks to report when the collision is high in a
specific subcarrier block number.
[0076] FIG. 6 shows transmission and reception of a signal between
base station apparatus 200 and communication terminal apparatus
100, and FIG. 7 shows operations of communication terminal
apparatus 100 and base station apparatus 200. In addition, in FIG.
7, the horizontal axis shows the time, and communication terminal
apparatuses 100-1 and 100-2 have the same configuration as that of
communication terminal apparatus 100 as shown in FIG. 2. Further,
FIG. 7 describes a case where two communication terminal
apparatuses 100 communicate with base station apparatus 200, but
the number of communication terminal apparatuses 100 can be set
arbitrarily.
[0077] Communication terminal apparatus 100 transmits signaling
signal 300 of FIG. 4 in uplink (step ST501), and base station
apparatus 200 transmits CQI report control information 400 of FIG.
5 in downlink (step ST502). Described up to this point is the
processing of an initial report before controlling the number of
subcarrier blocks.
[0078] The operation when controlling the number of subcarrier
blocks to transmit the CQI after the initial report will be
described next. First, the operation when the collision does not
occur will be described.
[0079] By the processing of the initial report, base station
apparatus 200 commands communication terminal apparatus 100 to
transmit the CQI of at least one subcarrier block in
number-of-subcarrier-block #401. In addition, in base station
apparatus 200, the number of CQI designated in
number-of-subcarrier-block #401 is not limited to one, but may be
an arbitrary number.
[0080] Each of communication terminal apparatuses 100-1 and 100-2
measures the received quality of each subcarrier block in received
quality measuring section 110, and generates the CQI in CQI
generating section 111. Then, communication terminal apparatus 100
transmits one CQI of a subcarrier block, for example, with the best
received quality out of the generated pieces of CQI to base station
apparatus 200 (step ST601 and step ST602). FIG. 8 shows a format of
CQI 700 transmitted from communication terminal apparatuses 100-1
and 100-2. CQI 700 is comprised of subcarrier block number #701 to
report and MCS #702 showing the received quality of the subcarrier
block to report.
[0081] Next, base station apparatus 200 receiving the CQI performs
scheduling in scheduling section 210 based on the CQI. As a result
of the scheduling, subcarrier blocks are not allocated to
communication terminal apparatuses 100-1 and 100-2, and base
station apparatus 200 transmits the scheduling information showing
that no subcarrier block is allocated to each of communication
terminal apparatuses 100-1 and 100-2 (step ST603 and step
ST604).
[0082] Communication terminal apparatuses 100-1 and 100-2 receiving
the scheduling information extract the scheduling information in
scheduling information extracting section 107. Then, in
communication terminal apparatuses 100-1 and 100-2, control section
113 compares the number of reported subcarrier blocks with the
number of allocated subcarrier blocks, using comparing circuit 800
as shown in FIG. 9. As a result of the comparison, the number of
subcarrier blocks for which communication terminal apparatuses
100-1 and 100-2 have reported the CQI is "1", and the number of
subcarrier blocks allocated in base station apparatus 200 is "0".
Therefore, based on the comparison result outputted from comparing
circuit 800, control section 113 increases the number of subcarrier
blocks to report the CQI by one. In communication terminal
apparatuses 100-1 and 100-2, sort section 112 outputs two pieces of
the CQI. By this means, each of communication terminal apparatuses
100-1 and 100-2 transmits two pieces of the CQI to base station
apparatus 200 (step ST605 and step ST606).
[0083] Next, base station apparatus 200 receiving the CQI performs
scheduling in scheduling section 210 based on the CQI. As a result
of the scheduling, subcarrier blocks are not allocated to
communication terminal apparatuses 100-1 and 100-2, and base
station apparatus 200 transmits the scheduling information showing
that no subcarrier block is allocated to each of communication
terminal apparatuses 100-1 and 100-2 (step ST607 and step
ST608).
[0084] Communication terminal apparatuses 100-1 and 100-2 receiving
the scheduling information extract the scheduling information in
scheduling information extracting section 107. Then, in
communication terminal apparatuses 100-1 and 100-2, control section
113 compares the number of reported subcarrier blocks with the
number of allocated subcarrier blocks, using comparing circuit 800.
As a result of the comparison, the number of subcarrier blocks for
which communication terminal apparatuses 100-1 and 100-2 have
reported the CQI is "2", and the number of subcarrier blocks
allocated in base station apparatus 200 is "0". Therefore, based on
the comparison result outputted from comparing circuit 800, control
section 113 further increases the number of subcarrier blocks to
report the CQI by one. In communication terminal apparatuses 100-1
and 100-2, sort section 112 outputs three pieces of CQI. By this
means, each of communication terminal apparatuses 100-1 and 100-2
transmits three pieces of CQI to base station apparatus 200 (step
ST609 and step ST610).
[0085] Next, base station apparatus 200 receiving the CQI performs
scheduling in scheduling section 210 based on the CQI. As a result
of the scheduling, one subcarrier block is allocated to each of
communication terminal apparatuses 100-1 and 100-2, and base
station apparatus 200 transmits the scheduling information showing
that one subcarrier block is allocated to each of communication
terminal apparatuses 100-1 and 100-2 (step ST611 and step ST612).
At this point, base station apparatus selects an MCS based on the
CQI in scheduling section 210 and transmits the scheduling
information including the selected MCS.
[0086] Communication terminal apparatuses 100-1 and 100-2 receiving
the scheduling information extract the scheduling information in
scheduling information extracting section 107. Then, in
communication terminal apparatuses 100-1 and 100-2, control section
113 compares the number of reported subcarrier blocks with the
number of allocated subcarrier blocks, using comparing circuit 800.
As a result of the comparison, the number of subcarrier blocks for
which communication terminal apparatuses 100-1 and 100-2 have
reported the CQI is "3", and the number of subcarrier blocks
allocated in base station apparatus 200 is "1". Therefore, based on
the comparison result outputted from comparing circuit 800, control
section 113 decreases the number of subcarrier blocks to report the
CQI by one. In communication terminal apparatuses 100-1 and 100-2,
sort section 112 outputs two pieces of CQI. By this means, each of
communication terminal apparatuses 100-1 and 100-2 transmits two
pieces of CQI to base station apparatus 200 (step ST613 and step
ST614). Thereafter, communication terminal apparatuses 100-1 and
100-2 and base station apparatus 200 can adaptively control the
number of subcarrier blocks to transmit the CQI by repeating the
similar processing.
[0087] The comparison in comparing circuit 800 is not limited to
comparison between the number of subcarrier blocks for which each
of communication terminal apparatuses 100-1 and 100-2 has reported
the CQI and the number of subcarrier blocks allocated in base
station apparatus 200, and may be comparison between an allocation
rate, which is a ratio of the number of subcarrier blocks actually
allocated in base station 200 to the number of subcarrier blocks
for which each of communication terminal apparatuses 100-1 and
100-2 has reported the CQI, and a threshold. In this case,
communication terminal apparatuses 100-1 and 100-2 increase the
number of subcarrier blocks to report the CQI when the allocation
rate is smaller than the threshold, and decreases the number of
subcarrier blocks to report the CQI when the allocation rate is
equal to or greater than the threshold. In addition, the number of
subcarrier blocks to increase and the number of subcarrier blocks
to decrease are not limited to one, and it is possible to increase
or decrease subcarrier blocks by an arbitrary number. Further, the
number of subcarrier blocks to increase/decrease may be
changed.
[0088] The operation when the collision occurs will be described
next with reference to FIG. 7. For example, when the CQI reported
in step ST609 and step ST610 overlaps with each other in one
subcarrier block, base station apparatus 200 detects that the
collision occurs in collision measuring section 208, and generates
the collision information showing that the number of collisions is
one in collision information generating section 209. Then, base
station apparatus 200 transmits the collision information to
communication terminal apparatuses 100-1 and 100-2 (step ST611 and
step ST612).
[0089] Communication terminal apparatuses 100-1 and 100-2 receiving
the collision information extract the collision information in
collision information extracting section 109. Then, in
communication terminal apparatuses 100-1 and 100-2, control section
113 increases the number of subcarrier blocks to report the CQI by
one. In communication terminal apparatuses 100-1 and 100-2, sort
section 112 outputs four pieces of CQI. By this means, each of
communication terminal apparatuses 100-1 and 100-2 transmits four
pieces of CQI to base station apparatus 200 (step ST609 and step
ST610). At this point, in communication terminal apparatuses 100-1
and 100-2, control section 113 controls the number of subcarrier
blocks to report the CQI, further considering the result of
comparison between the number of reported subcarrier blocks and the
number of allocated subcarrier blocks in comparing circuit 800, in
addition to the collision information.
[0090] In addition, communication terminal apparatuses 100-1 and
100-2 may consider one of the collision information and the
comparison result in comparing circuit 800, in addition to
considering both the collision information and the comparison
result in comparing circuit 800. For example, in the case of
considering only the comparison result in comparing circuit 800,
communication terminal apparatuses 100-1 and 100-2 compare a
cumulative allocation rate, which is a ratio of the number of
actually allocated subcarrier blocks to the number of reports
within predetermined previous time, or an average value with a
threshold. As a result of comparison, communication terminal
apparatuses 100-1 and 100-2 increase the number of subcarrier
blocks to report the CQI when the cumulative allocation rate or
average value is smaller than the threshold, and decreases the
number of subcarrier blocks to report the CQI when the cumulative
allocation rate or average value is equal to or greater than the
threshold. By this means, as compared with the case where the base
station apparatus transmits the collision information, it is
possible to reduce overhead due to signaling in downlink. Further,
the number of subcarrier blocks to increase and the number of
subcarrier blocks to decrease are not limited to one, and it is
possible to increase or decrease subcarrier blocks by an arbitrary
number. Furthermore, the number of subcarrier blocks to
increase/decrease may be changed.
[0091] FIGS. 10 and 11 show the method of grouping a plurality of
subcarriers in a predetermined communication band and forming a
subcarrier block. In the method in FIG. 10, a predetermined number
of subcarriers in a predetermined communication band (for example,
20 MHz) #901 are selected sequentially from the end and grouped to
form N (N is a natural number of two or more) subcarrier blocks, G1
to GN. In the method of FIG. 11, a predetermined number of
non-consecutive subcarriers at fixed intervals in a predetermined
communication band (for example, 20 MHz) #1001 are selected and
grouped to form N subcarrier blocks, G1 to GN.
[0092] Thus, according to Embodiment 1, based on a result of
comparison between the number of subcarrier blocks for which the
communication terminal apparatus has reported the CQI and the
number of actually allocated subcarrier blocks, or based on the
collision information, the number of subcarrier blocks for which
the communication terminal apparatus reports the CQI is controlled,
so that it is possible to reduce the interference in uplink without
wasting reports of received quality, perform optimal allocation by
scheduling, prevent resources from being lost, and maintain
fairness of transmission allocation by scheduling.
[0093] In addition, in Embodiment 1, communication terminal
apparatus 100 includes an MCS in CQI to report the received
quality, but this is by no means limiting, and communication
terminal apparatus 100 may include an SINR in CQI to report the
received quality. FIG. 12 shows a format of CQI 1100 when the
received quality is reported with an SINR included in CQI. CQI 1100
is comprised of subcarrier block number #1101 to report and SINR
#1102 measured in received quality measuring section 110.
Embodiment 2
[0094] FIG. 13 is a block diagram showing a configuration of
comparing circuit 1200 according to Embodiment 2 of the present
invention. In addition, in Embodiment 2, a configuration of a
communication terminal apparatus is the same as that in FIG. 2, a
configuration of a base station apparatus is the same as that in
FIG. 3, and so descriptions thereof will be omitted.
[0095] In communication terminal apparatuses 100-1 and 100-2, using
comparing circuit 1200 in FIG. 13, control section 113 compares a
desired transmission rate by the reported CQI and a transmission
rate actually assigned in base station apparatus 200. In addition,
communication terminal apparatuses 100-1 and 100-2 are capable of
knowing the assigned transmission rate by receiving the scheduling
information. Further, as the transmission rate, for example, a bit
rate is used.
[0096] As a result of comparison, control section 113 increases the
number of subcarrier blocks to report the CQI when the transmission
rate assigned in base station apparatus 200 is smaller than the
desired transmission rate desired by communication terminal
apparatuses 100-1 and 100-2, and decreases the number of subcarrier
blocks to report the CQI when the transmission rate assigned in
base station apparatus 200 is the same as the desired transmission
rate desired by communication terminal apparatuses 100-1 and 100-2.
In addition, the operations of the communication terminal apparatus
and base station apparatus are the same as those in Embodiment 1
except the configuration for comparing the number of subcarrier
blocks for which the CQI has been reported with the number of
actually allocated subcarrier blocks being replaced with the
configuration for comparing the desired transmission rate by the
reported CQI with the number of actually allocated subcarrier
blocks, and so descriptions thereof will be omitted.
[0097] Thus, according to Embodiment 2, based on a result of
comparison between the desired transmission rate by the CQI
reported by the communication terminal apparatus and the actually
assigned transmission rate, or based on the collision information,
the number of subcarrier blocks for which the communication
terminal apparatus reports the CQI is controlled, so that it is
possible to reduce the interference in uplink without wasting
reports of received quality, perform optimal allocation by
scheduling, prevent resources from being lost, and maintain
fairness of transmission allocation by scheduling.
[0098] In addition, in Embodiment 2, the number of subcarrier
blocks is controlled based on a result of comparison between the
desired transmission rate and actually assigned transmission rate,
but this is by no means limiting, and the number of subcarrier
blocks may be controlled based on a result of comparison between a
ratio of the actually assigned transmission rate to the desired
transmission rate and a threshold. In this case, the number of
subcarrier blocks to transmit the CQI increases when the ratio of
the actually assigned transmission rate to the desired transmission
rate is smaller than the threshold, and decreases when the ratio of
the actually assigned transmission rate to the desired transmission
rate is equal to or greater than the threshold.
Embodiment 3
[0099] FIG. 14 shows an instantaneous allocation rate and a
cumulative allocation rate measured in a communication terminal
apparatus according to Embodiment 3 of the present invention. In
addition, in Embodiment 3, a configuration of the communication
terminal apparatus is the same as that in FIG. 2, a configuration
of a base station apparatus is the same as that in FIG. 3, and so
descriptions thereof will be omitted. Further, in FIG. 14, SCB is a
subcarrier block.
[0100] From FIG. 14, the number of reports or report time number
(A) is the number of times or time number that the communication
terminal apparatus reports the CQI to the base station apparatus,
and, for example, the communication terminal apparatus reports in
one TTI cycle. Further, the number of report subcarrier blocks (B)
designated from the base station apparatus (Node B) is the number
of subcarrier blocks to report the CQI, which is designated from
the base station apparatus to the communication terminal apparatus,
and is all "1" in the case of FIG. 14. (B) is designated by
number-of-subcarrier-block #401 in CQI report control information
400 of FIG. 5. Further, the number of reported subcarrier blocks
(SCB) (C) is the number of subcarrier blocks for which the
communication terminal apparatus has reported the CQI to the base
station apparatus.
[0101] Furthermore, the number of actually allocated subcarrier
blocks (SCB) (D) is the number of subcarrier blocks actually
allocated by scheduling in the base station apparatus. Still
furthermore, the instantaneous allocation rate (E) is obtained from
(D)/(B). Moreover, the cumulative allocation rate (F) is obtained
from (Total of (D))/(A).
[0102] Control section 113 of communication terminal apparatus 100
compares (E) or (F) with the threshold, and commands to increase
the number of subcarrier blocks to report the CQI when (E) or (F)
is smaller than the threshold, and commands to decrease the number
of subcarrier blocks to report the CQI when (E) or (F) is equal to
or greater than the threshold.
[0103] Thus, according to Embodiment 3, based on the instantaneous
allocation rate or the cumulative allocation rate, or based on the
collision information, the number of subcarrier blocks for which
the communication terminal apparatus reports the CQI is controlled,
so that it is possible to reduce the interference in uplink without
wasting reports of received quality, perform optimal allocation by
scheduling, prevent resources from being lost, and maintain
fairness of transmission allocation by scheduling.
Embodiment 4
[0104] FIG. 15 shows a subcarrier block for which each
communication terminal apparatus reports CQI according to
Embodiment 4 of the present invention. In addition, In Embodiment
4, a configuration of the communication terminal apparatus is the
same as that in FIG. 2, a configuration of a base station apparatus
is the same as that in FIG. 3, and so descriptions thereof will be
omitted.
[0105] FIG. 15 shows the case where eight communication terminal
apparatuses communicate with a single base station apparatus, for
example, and the total number of subcarrier blocks is eight, for
example. In addition, in FIG. 15, SCB is a subcarrier block, and
UE1 to UE8 are the communication terminal apparatuses. Further, in
FIG. 15, for convenience in description, a case will be described
where each communication terminal apparatus reports the CQI for two
subcarrier blocks, but the present invention is applicable to a
case where each communication terminal apparatus individually
reports the CQI for an arbitrary number of three or more subcarrier
blocks.
[0106] When control section 113 of each communication terminal
apparatus 100 judges that the CQI of one subcarrier block is
outputted based on the number of subcarrier blocks for which the
CQI has been transmitted and the number of actually allocated
subcarrier blocks, control section 113 actually increases the
number of subcarrier blocks to transmit the CQI by one, and
commands sort section 112 to output the CQI for two subcarrier
blocks (No. 1 and No. 2). As a result, each communication terminal
apparatus transmits the CQI of two subcarrier blocks. For example,
when UE1 transmits one CQI, UE1 collides with UE6 in subcarrier
block 1, and so no subcarrier block is allocated to UE1 when the
base station apparatus allocates subcarrier block 1 to UE6.
However, in Embodiment 4, UE1 reports the CQI also for subcarrier
block 2, and so there is the possibility that subcarrier block 2 is
allocated to UE1.
[0107] FIG. 16 shows a format of CQI 1500 transmitted from each of
communication terminal apparatuses UE1 to UE8. CQI 1500 is
comprised of subcarrier block number #1501 to report and MCS #1502
showing the received quality of the subcarrier block to report.
[0108] Thus, according to Embodiment 4, in addition to the effect
of above-mentioned Embodiment 1, by providing the number of
subcarrier blocks to report the CQI with redundancy, it is possible
to increase the probability of allocating transmission.
[0109] In addition, Embodiment 4 is applicable to above-mentioned
Embodiment 2 or 3.
Embodiment 5
[0110] FIG. 17 is a block diagram showing a configuration of
communication terminal apparatus 1600 according to Embodiment 5 of
the present invention.
[0111] Communication terminal apparatus 1600 according to
Embodiment 5 of the present invention eliminates collision
information extracting section 109 and control section 113, as
shown in FIG. 17, in communication terminal apparatus 100 according
to Embodiment 1 as shown in FIG. 2. In addition, in FIG. 17, the
same components as those in FIG. 2 will be assigned the same
reference numerals, and so descriptions thereof will be
omitted.
[0112] FFT section 104 performs FFT on a received signal inputted
from GI removing section 103 and outputs the result to demodulation
section 105, scheduling information extracting section 107 and
received quality measuring section 110.
[0113] Scheduling information extracting section 107 extracts the
scheduling information that is included in the received signal
inputted from FFT section 104 and that is information of a result
of the processing of allocating resources for each subcarrier block
in the base station apparatus, and outputs the scheduling
information to selecting section 108 and sort section 112.
[0114] Based on a measurement result inputted from received quality
measuring section 110, CQI generating section 111 generates CQI
that is information showing the measurement result and outputs the
CQI to sort section 112. At this point, CQI generating section 111
generates the CQI per subcarrier block.
[0115] Sort section 112 sorts the CQI inputted from CQI generating
section 111 in descending order of the received quality or in
ascending order of the received quality. Then, sort section 112
outputs the sorted CQI corresponding to the number designated from
control section 113 to multiplexing section 114 in descending order
of the received quality.
[0116] A configuration of base station apparatus 1700 will be
described next with reference to FIG. 18. FIG. 18 is a block
diagram showing the configuration of base station apparatus
1700.
[0117] Base station apparatus 1700 according to Embodiment 5
eliminates collision information generating section 209 and adds
calculating section 1701 and control section 1702, as shown in FIG.
18, in base station apparatus 200 according to Embodiment 1 as
shown in FIG. 3. In addition, the same components as those in FIG.
3 will be assigned the same reference numerals, and so descriptions
thereof will be omitted.
[0118] CQI extracting section 207 extracts the CQI from a received
signal inputted from error correction decoding section 206, and
outputs the extracted CQI to collision measuring section 208,
scheduling section 210 and calculating section 1701.
[0119] Collision measuring section 208 measures collision based on
the CQI inputted from CQI extracting section 207. More
specifically, collision measuring section 208 measures the number
of collisions for each subcarrier block. Then, collision measuring
section 208 outputs a measurement result of the number of
collisions to control section 1702.
[0120] Scheduling section 210 performs scheduling based on the CQI
inputted from CQI extracting section 207. For example, scheduling
section 210 assigns a communication terminal apparatus that has
transmitted the CQI with the best received quality for each
subcarrier block, and selects an MCS of a combination of the coding
rate and modulation scheme corresponding to the transmitted CQI.
Then, scheduling section 210 outputs the information of the
subcarrier block allocated to each communication terminal apparatus
and MCS to scheduling information generating section 211 and
calculating section 1701.
[0121] Calculating section 1701 compares the CQI inputted from CQI
extracting section 207 with the scheduling information inputted
from scheduling section 201, and outputs the comparison result to
control section 1702.
[0122] Based on the measurement result of the collision inputted
from collision measuring section 208 and the comparison result
inputted from calculating section 1701, control section 1702
controls the number of subcarrier blocks for which communication
terminal apparatus 1600 reports the CQI at next TTI. Then, control
section 1702 outputs the information of the controlled number of
subcarrier blocks to scheduling information generating section
211.
[0123] Scheduling information generating section 211 generates
scheduling information including the information of the subcarrier
block allocated to each communication terminal apparatus and MCS
inputted from scheduling section 210, and the information of the
number of subcarrier blocks inputted from control section 1702 and
outputs the scheduling information to multiplexing section 212.
[0124] The operations of communication terminal apparatus 1600 and
base station apparatus 1700 will be described next. In addition, a
format of a signaling signal is the same as that in FIG. 4, a
format of CQI report control information is the same as that in
FIG. 4, and so descriptions thereof will be omitted.
[0125] FIG. 19 shows the operations of base station apparatus 1700
and communication terminal apparatus 1600. In addition, in FIG. 19,
the horizontal axis shows the time, and communication terminal
apparatuses 1600-1 and 1600-2 have the same configuration as that
of communication terminal apparatus 1600 as shown in FIG. 17.
Further, FIG. 19 describes the case where two communication
terminal apparatuses 1600 communicate with base station apparatus
1700, but the number of communication terminal apparatuses 1600 may
be an arbitrary number.
[0126] Communication terminal apparatus 1600 transmits signaling
signal 300 of FIG. 4 in uplink, and base station apparatus 1700
transmits CQI report control information 400 of FIG. 5 in downlink.
In this way, the processing is finished for an initial report
before controlling the number of subcarrier blocks. In addition,
the other initial report processing is the same as in
above-mentioned Embodiment 1, and so descriptions thereof will be
omitted.
[0127] The operation for controlling the number of subcarrier
blocks to transmit the CQI after the initial report will be
described next. First, the operation when the collision does not
occur will be described.
[0128] By the processing of the initial report, base station
apparatus 1700 commands communication terminal apparatuses 1600-1
and 1600-2 to transmit the CQI of at least one subcarrier block in
number-of-subcarrier-block #401. In addition, in base station
apparatus 1700, the number of CQI designated in
number-of-subcarrier-block #401 is not limited to one but may be an
arbitrary number.
[0129] Each of communication terminal apparatuses 1600-1 and 1600-2
measures the received quality of each subcarrier block in received
quality measuring section 110, and generates the CQI in CQI
generating section 111. Then, each of communication terminal
apparatuses 1600-1 and 1600-2 transmits one CQI of a subcarrier
block, for example, with the best received quality among generated
pieces of the CQI to base station apparatus 1700 (step ST1801 and
step ST1802). In addition, the format of the CQI is the same as in
FIG. 8, and so descriptions thereof will be omitted.
[0130] Base station apparatus 1700 receiving the CQI does not
allocate any subcarrier block to communication terminal apparatuses
1600-1 and 1600-2, as a result of scheduling in scheduling section
210. Accordingly, in base station apparatus 1700, calculating
section 1701 outputs such a comparison result that the number of
subcarrier blocks for which the CQI has been received is "1" and
that the number of actually allocated subcarrier blocks is "0",
control section 1702 increases the number of subcarrier blocks to
report the CQI by one, and thus, determines that the CQI of two
subcarrier blocks is transmitted, and scheduling information
generating section 211 generates the scheduling information with
the information of the number of subcarrier blocks showing that the
number of subcarrier blocks to report the CQI is "2". Accordingly,
base station apparatus 1700 transmits the scheduling information
including the information that no subcarrier block is allocated and
the information of the number of subcarrier blocks showing that the
number of subcarrier blocks to report the CQI is "2" (step ST1803
and step ST1804).
[0131] Next, each of communication terminal apparatuses 1600-1 and
1600-2 measures the received quality of each subcarrier block in
received quality measuring section 110, and generates the CQI in
CQI generating section 111. Then, communication terminal
apparatuses 1600-1 and 1600-2 transmit a number of pieces of CQI
which are designated in the scheduling information, for example,
two pieces of CQI of two respective subcarrier blocks with the best
and second best received quality among generated pieces of CQI to
base station apparatus 1700 (step ST1805 and step ST1806). The
format of the CQI is the same as in FIG. 8, and so descriptions
thereof will be omitted.
[0132] Next, base station apparatus 1700 receiving the CQI does not
allocate any subcarrier block to communication terminal apparatuses
1600-1 and 1600-2, as a result of scheduling in scheduling section
210. Accordingly, in base station apparatus 1700, calculating
section 1701 outputs such a comparison result that the number of
subcarrier blocks for which the CQI has been received is "2" and
that the number of actually allocated subcarrier blocks is "0",
control section 1702 further increases the number of subcarrier
blocks to report the CQI by one, and thus, determines that the CQI
of three subcarrier blocks is transmitted, and scheduling
information generating section 211 includes the information of the
number of subcarrier blocks showing that the number of subcarrier
blocks to report the CQI is "3" in the scheduling information.
Accordingly, base station apparatus 1700 transmits the scheduling
information including the information that no subcarrier block is
allocated and the information of the number of subcarrier blocks
showing that the number of subcarrier blocks to report the CQI is
"3" (step ST1807 and step ST1808).
[0133] Next, each of communication terminal apparatuses 1600-1 and
1600-2 measures the received quality of each subcarrier block in
received quality measuring section 110, and generates the CQI in
CQI generating section 111. Then, communication terminal
apparatuses 1600-1 and 1600-2 transmit a number of pieces of CQI
which are designated in the scheduling information, for example,
three pieces of CQI of three respective subcarrier blocks with the
best, second best and third best received quality among generated
pieces of CQI to base station apparatus 1700 (step ST1809 and step
ST1810).
[0134] Next, base station apparatus 1700 receiving the CQI
allocates one subcarrier block to each of communication terminal
apparatuses 1600-1 and 1600-2, as a result of scheduling in
scheduling section 210. Accordingly, in base station apparatus
1700, calculating section 1701 outputs such a comparison result
that the number of subcarrier blocks for which the CQI has been
received is "3" and that the number of actually allocated
subcarrier blocks is "1", control section 1702 decreases the number
of subcarrier blocks to report the CQI by one, and thus, determines
that the CQI of two subcarrier blocks is transmitted, and
scheduling information generating section 211 includes the
information of the number of subcarrier blocks showing that the
number of subcarrier blocks to report the CQI is "2" in the
scheduling information. Accordingly, base station apparatus 1700
transmits the scheduling information including the information that
one subcarrier block is allocated and the information of the number
of subcarrier blocks showing that the number of subcarrier blocks
to report the CQI is "2" (step ST1811 and step ST1812).
[0135] Next, each of communication terminal apparatuses 1600-1 and
1600-2 measures the received quality of each subcarrier block in
received quality measuring section 110, and generates the CQI in
CQI generating section 111. Then, communication terminal
apparatuses 1600-1 and 1600-2 transmit a number of pieces of CQI
which are designated in the scheduling information, for example,
two pieces of CQI of two respective subcarrier blocks with the best
and second best received quality among generated pieces of CQI to
base station apparatus 1700 (step ST1813 and step ST1814).
Thereafter, communication terminal apparatuses 1600-1 and 1600-2
and base station apparatus 1700 can adaptively control the number
of subcarrier blocks to transmit the CQI by repeating the similar
processing. In addition, the number of subcarrier blocks to
increase and the number of subcarrier blocks to decrease are not
limited to one, and it is possible to increase or decrease
subcarrier blocks by an arbitrary number. Further, the number of
subcarrier blocks to increase/decrease may be changed.
[0136] Next, the operation when the collision occurs will be
described next with reference to FIG. 19. For example, when the CQI
reported in step ST1809 and step ST1810 overlaps with each other in
one subcarrier block, base station apparatus 1700 detects that the
collision with the number of collisions of "1" occurs in collision
measuring section 208. Then, base station apparatus 1700 determines
to increase the number of subcarrier blocks to report the CQI by
one in control section 1702. Next, base station apparatus 1700
increases the number of subcarrier blocks by one and transmits the
scheduling information including the information of the number of
subcarrier blocks that the number of subcarrier blocks is "4".
Then, communication terminal apparatuses 1600-1 and 1600-2 extract
the scheduling information in scheduling information extracting
section 107, and output four pieces of CQI in sort section 112. By
this means, each of communication terminal apparatuses 1600-1 and
1600-2 transmits four pieces of CQI to base station apparatus 1700
(step ST1809 and step ST1810). Herein, when controlling the number
of subcarrier blocks to report the CQI, control section 1702 of
base station apparatus 1700 controls the number of subcarrier
blocks to report the CQI, further considering the result of
comparison between the number of subcarrier blocks for which the
CQI has been received and the number of allocated subcarrier blocks
in comparing circuit 800, in addition to the number of collisions.
In addition, base station apparatus 1700 may consider one of the
number of collisions and the comparison result in comparing circuit
800, in addition to considering both the number of collisions and
the comparison result in comparing circuit 800. Further, the number
of subcarrier blocks to increase and the number of subcarrier
blocks to decrease are not limited to one, and it is possible to
increase or decrease subcarrier blocks by an arbitrary number.
Furthermore, the number of subcarrier blocks to increase/decrease
may be changed.
[0137] Thus, according to Embodiment 5, based on a result of
comparison between the number of subcarrier blocks for which the
communication terminal apparatus has reported the CQI and the
number of actually allocated subcarrier blocks, or based on the
collision information, the number of subcarrier blocks for which
the communication terminal apparatus reports the CQI is controlled,
so that it is possible to reduce the interference in uplink without
wasting reports of received quality, perform optimal allocation by
scheduling, prevent resources from being lost, and maintain
fairness of transmission allocation by scheduling.
[0138] In addition, in above-mentioned Embodiments 2 to 4, when
control section 1702 in the base station apparatus controls the
number of subcarrier blocks to transmit the CQI, Embodiment 5 is
applicable to above-mentioned Embodiments 2 to 4.
Embodiment 6
[0139] FIG. 20 shows comparing circuit 1900 according to Embodiment
6 of the present invention. In addition, in Embodiment 6, a
configuration of a communication terminal apparatus is the same as
that in FIG. 17, a configuration of a base station apparatus is the
same as that in FIG. 18, and so descriptions thereof will be
omitted.
[0140] In base station apparatus 1700, control section 113 compares
collisions and an allocation rate that is a ratio of the number of
subcarrier blocks actually allocated by scheduling to the number of
subcarrier blocks of received CQI with thresholds, using comparing
circuit 1900 as shown in FIG. 20. Based on a result of the
comparison, control section 113 increases the number of subcarrier
blocks to report the CQI when the collisions or the allocation rate
is smaller than the threshold, and decreases the number of
subcarrier blocks to report the CQI when the collisions or the
allocation rate is equal to or greater than the threshold. In
addition, operations of the communication terminal apparatus and
the base station apparatus are the same as in above-mentioned
Embodiment 5, and so descriptions thereof will be omitted.
[0141] FIG. 21 shows circumstances of collisions of subcarrier
blocks for which communication terminal apparatuses transmit the
CQI measured in the base station apparatus. In FIG. 21, the same
numeric value in report time (A) shows the same time. Further,
report subcarrier block number (B) is a subcarrier block number
that each communication terminal apparatus reports to the base
station apparatus, and shows that there are eight subcarrier blocks
from number 1 to number 8 in total in the case of FIG. 21.
Furthermore, the number of CQI reports (C) of an arbitrary
subcarrier block is the number that the CQI is reported in a single
subcarrier block selected arbitrarily. In addition, collision
factor (D) of an arbitrary subcarrier block is the same numeric
value as that of (C). Further, distribution (E) of UE reports shows
distribution circumstances of each subcarrier block for which a
plurality of communication terminal apparatuses report at the same
time. Furthermore, the number of all UEs (F) shows the number of
communication terminal apparatuses existing in the cell, and in the
case of FIG. 21, the number of communication terminal apparatuses
is "16". UE based cumulative/instantaneous allocation rate (G) is
cumulative allocation rate/instantaneous allocation rate of each
communication terminal apparatus. UE based desired/actual bit rate
(H) is desired bit rate/actually assigned bit rate of each
communication terminal apparatus. UE based report frequency range
(I) is the frequency range in which each communication terminal
apparatus reports the CQI.
[0142] Control section 1702 of base station apparatus 1700 compares
(D) with a threshold in comparing circuit 1900, and controls to
increase the number of subcarrier blocks to report the CQI when (D)
is smaller than the threshold, and controls to decrease the number
of subcarrier blocks to report the CQI when (D) is equal to or
greater than the threshold.
[0143] Thus, according to Embodiment 6, based on the allocation
rate or the collision information, the number of subcarrier blocks
for which the communication terminal apparatus reports the CQI is
controlled, so that it is possible to reduce the interference in
uplink without wasting reports of received quality, perform optimal
allocation by scheduling, prevent resources from being lost, and
maintain fairness of transmission allocation by scheduling.
Embodiment 7
[0144] FIG. 22 is a block diagram showing a configuration of
communication terminal apparatus 2100 according to Embodiment 7 of
the present invention.
[0145] As shown in FIG. 22, communication terminal apparatus 2100
according to Embodiment 7 is further provided with ON/OFF control
information extracting section 2101 in communication terminal
apparatus 100 according to Embodiment 1 as shown in FIG. 2. In
addition, in FIG. 22, the same components as those in FIG. 2 will
be assigned the same reference numerals, and so descriptions
thereof will be omitted.
[0146] FFT section 104 performs FFT on a received signal inputted
from GI removing section 103 and outputs the result to demodulation
section 105, scheduling information extracting section 107,
collision information extracting section 109, received quality
measuring section 110 and ON/OFF control information extracting
section 2101.
[0147] ON/OFF control information extracting section 2101 extracts
ON/OFF control information that is information to switch between
transmission and non-transmission of CQI from the received signal
inputted from FFT section 104 and outputs the ON/OFF control
information to control section 103.
[0148] Control section 113 designates the number of subcarrier
blocks to output the CQI, to sort section 112, based on the
information of the number of subcarrier blocks for which the CQI
has been transmitted and which is inputted from CQI generating
section 111, the collision information inputted from collision
information extracting section 109, and the scheduling information
inputted from scheduling information extracting section 107.
Further, when the ON/OFF control information to stop the
transmission of CQI is inputted from ON/OFF control information
extracting section 2101, control section 113 commands sort section
112 to stop the output of CQI of the designated number of
subcarrier blocks. Furthermore, when the ON/OFF control information
to resume the transmission of CQI is inputted from ON/OFF control
information extracting section 2101, control section 113 commands
sort section 112 to resume the output of CQI of the designated
number of subcarrier blocks.
[0149] A configuration of base station apparatus 2200 will be
described with reference to FIG. 23. FIG. 23 is a block diagram
showing the configuration of base station apparatus 2200.
[0150] As shown in FIG. 23, base station apparatus 2200 according
to Embodiment 7 is further provided with number-of-terminal
monitoring section 2201 and ON/OFF control information generating
section 2202 in base station apparatus 200 according to Embodiment
1 as shown in FIG. 3. In addition, in FIG. 23, the same components
as those in FIG. 3 will be assigned the same reference numerals,
and descriptions thereof will be omitted.
[0151] Error correction decoding section 206 performs error
correction decoding on a received signal inputted from demodulation
section 205 and outputs the result to CQI extracting section 207
and number-of-terminal monitoring section 2201, and outputs the
result as a received signal.
[0152] Number-of-terminal monitoring section 2201 counts the number
of communication terminal apparatuses 2100 currently communicating,
at a predetermined timing, from the received signal inputted from
error correction decoding section 206. Then, when detecting that
the counted number of communication terminal apparatuses 2100 turns
from the number smaller than a threshold to the number equal to or
larger than the threshold, number-of-terminal monitoring section
2201 outputs information that the number of communication terminal
apparatuses 2100 is equal to or larger than the threshold to ON/OFF
control information generating section 2202. Further, when
detecting that the counted number of communication terminal
apparatuses 2100 turns from the number equal to or larger than the
threshold to the number smaller than the threshold,
number-of-terminal monitoring section 2201 outputs information that
the number of communication terminal apparatuses 2100 is smaller
than the threshold to ON/OFF control information generating section
2202.
[0153] When the information that the number of communication
terminal apparatuses 2100 becomes equal to or larger than the
threshold is inputted from number-of-terminal monitoring section
2201, ON/OFF control information generating section 2202 generates
the ON/OFF control information to stop the transmission of CQI and
outputs the ON/OFF control information to multiplexing section 212.
Meanwhile, when the information that the number of communication
terminal apparatuses 2100 becomes smaller than the threshold is
inputted from number-of-terminal monitoring section 2201, ON/OFF
control information generating section 2202 generates the ON/OFF
control information to resume the transmission of CQI and outputs
the ON/OFF control information to multiplexing section 212.
[0154] Multiplexing section 212 multiplexes the transmission
signal, pilot signal, collision information inputted from collision
information generating section 209, scheduling information inputted
from scheduling information generating section 211 and ON/OFF
control information inputted from ON/OFF control information
generating section 2202, generates a multiplexed signal, and
outputs the generated multiplexed signal to error correction coding
section 213.
[0155] Operations of communication terminal apparatus 2100 and base
station apparatus 2200 will be described next with reference to
FIG. 24. FIG. 24 shows a CQI transmission timing of each
communication terminal apparatus. In addition, communication
terminal apparatuses 2100 (UE1 to UE3) are communicating with the
same base station apparatus 2200.
[0156] In base station apparatus 2200, when number-of-terminal
monitoring section 2201 detects that the number of communication
terminal apparatuses in communication turns from the number smaller
than the threshold to the number equal to or larger than the
threshold, ON/OFF control information generating section 2202
generates the ON/OFF control information to stop the transmission
of CQI of communication terminal apparatus 2100 (UE2) and
communication terminal apparatus 2100 (UE3) at time t1. Then, base
station apparatus 2200 transmits the ON/OFF control information. In
communication terminal apparatus 2100 (UE2) and communication
terminal apparatus 2100 (UE3) receiving the ON/OFF control
information, ON/OFF control information extracting section 2101
extracts the ON/OFF control information, and control section 113
commands sort section 112 to stop the output of CQI from time t1.
By this means, communication terminal apparatus 2100 (UE2) and
communication terminal apparatus 2100 (UE3) stop the transmission
of CQI from time t1. Meanwhile, communication terminal apparatus
2100 (UE1) is not commanded to stop the transmission of CQI by the
ON/OFF control information, and so continues the transmission of
CQI.
[0157] Subsequently, ON/OFF control information generating section
2202 generates the ON/OFF control information to stop the
transmission of CQI of communication terminal apparatus 2100 (UE1),
and generates the ON/OFF control information to resume the
transmission of CQI of communication terminal apparatus 2100 (UE2)
at time t2. Then, base station apparatus 2200 transmits the ON/OFF
control information. In communication terminal apparatus 2100 (UE1)
and communication terminal apparatus 2100 (UE2) receiving the
ON/OFF control information, ON/OFF control information extracting
section 2101 extracts the ON/OFF control information. Then, in
communication terminal apparatus 2100 (UE1), control section 113
commands sort section 112 to stop the output of CQI from time t2.
Meanwhile, in communication terminal apparatus 2100 (UE2) control
section 113 commands sort section 112 to resume the output of CQI
from time t2. By this means, at time t2, communication terminal
apparatus 2100 (UE1) stops the transmission of CQI, and
communication terminal apparatus 2100 (UE1) resumes the
transmission of CQI. Meanwhile, communication terminal apparatus
2100 (UE3) is not commanded to resume the transmission of CQI by
the ON/OFF control information, and so continues to stop the
transmission of CQI. Thereafter, at time t3, t4 and t5, similar
operations are carried out.
[0158] Thus, according to Embodiment 7, in addition to the effect
of above-mentioned Embodiment 1, when the number of communication
terminal apparatuses is large, the transmission of CQI from a
predetermined number of communication terminal apparatuses is made
to stop, so that it is possible to increase the probability of
allocating transmission to the communication terminal apparatus
that has transmitted the CQI.
[0159] In addition, in Embodiment 7, the ON/OFF control information
is generated based on the number of communication terminal
apparatuses with which the base station apparatus is communicating,
but the present invention is not limited thereto. The ON/OFF
control information may be generated based on the traffic status
within the cell, the collision status of a subcarrier block for
which the CQI is transmitted among communication terminal
apparatuses, the allocation rate or the like.
[0160] In above-mentioned Embodiments 1 to 7, in the communication
terminal apparatus, sort section 112 rearranges the CQI, but the
present invention is not limited thereto. Sort section 112 may be
removed and the CQI may be outputted to multiplexing section 114
from CQI generating section 111 without being rearranged. In this
case, CQI generating section 111 may output the CQI in descending
order of the received quality among an arbitrary sequence of the
CQI, or may output the CQI selected arbitrarily irrespective of the
received quality. Further, in above-mentioned Embodiments 1 to 7,
the number of subcarrier blocks to transmit the CQI may be
controlled based on a result of comparison between QoS requested
from the communication terminal apparatus and QoS of a result of
allocation of resources in the base station apparatus. In this
case, when QoS requested by the communication terminal apparatus is
satisfied, the number of subcarrier blocks is decreased, and, when
QoS requested by the communication terminal is not satisfied, the
number of subcarrier blocks is increased. Furthermore, in
above-mentioned Embodiments 1 to 7, the communication terminal
apparatus reports the received quality using the CQI, but the
present invention is not limited thereto. The communication
terminal apparatus may report the received quality using arbitrary
means other than the CQI.
[0161] Moreover, in above-mentioned Embodiments 1 to 7, the base
station apparatus commands the communication terminal apparatus
using CQI report control information 400 in initial reporting,
based on signaling signal 300 transmitted from the communication
terminal apparatus, but the present invention is not limited
thereto. The base station apparatus may command the communication
terminal apparatus using CQI report control information 400 also
after the initial reporting, based on signaling signal 300. In this
case, the base station apparatus directly designates a cycle, time
offset, and frequency range for reporting the CQI to communication
terminal apparatuses, and disperses the CQI transmitted from the
communication terminal apparatuses in domains of time, frequency
and the like, so that it is possible to improve CQI report
efficiency in uplink and reduce the interference in uplink.
Further, when the number of communication terminal apparatuses
within the cell is large, the base station apparatus divides the
entire bandwidth into a plurality of portions, divides the
communication terminal apparatuses into a plurality of groups and
assigns communication terminal apparatuses of different groups to
different frequency ranges in advance, so that it is possible to
reduce collisions in CQI transmission of the communication terminal
apparatuses.
INDUSTRIAL APPLICABILITY
[0162] The communication terminal apparatus, base station apparatus
and received quality reporting method according to the present
invention are suitable particularly for reporting the received
quality in uplink in multicarrier transmission schemes.
* * * * *